Various apparatus and methods have previously been devised for aligning sights on firearms. U.S. Pat. No. 3,744,133 to Fukushima, et al., for example, describes a collimating device having a bore support member and an upstanding member with a sighting grid for adjusting telescopic sights on firearms. One variation of the disclosed apparatus includes fitting a light reducing member at the front, i.e. objective lens, of the telescopic sight to be aligned. The disclosed method for using the device is to adjust the alignment of the optic axis of a telescopic sight so it is parallel to that of the bore of the firearm on which the telescopic sight is mounted. There is no provision for adjusting alignment of the collimating device after sighting in a firearm by firing ammunition to compensate for misalignment between projectile trajectory and the axis of the bore so the collimating device can be retained as a master for that firearm and others of its type, i.e. caliber and action-type. Further this collimating device is only disclosed for alignment of telescopic sights, neither open or aperture iron sights are considered.
Variations of collimating devices to that disclosed in U.S. Pat. No. 3,744,133 include use of an objective lens mounted on a tube also mounting a sighting grid. The objective lens is fixed at its focal length from the sighting grid. This collimator tube arrangement is again mounted to a firearm using a bore support member, so the collimator optic axis is parallel to the firearm bore axis. But as with the collimating device disclosed in U.S. Pat. No. 3,744,133 there is no provision for adjusting alignment of the sight grid in the collimator, and therefore the optic axis, after sighting in a firearm to compensate for misalignment between projectile trajectory and the axis of the bore so the collimator can be retained as a master for that firearm and others of its type, i.e. caliber and action-type.
Still another variation of known firearm sight alignment collimating devices includes an objective lens with sighting grid collimator arrangement intended to be mounted on a bore support member. For this device, alignment of the sighting grid is adjustable. The intended use is for alignment of military firearms. A weapon of one type, i.e. caliber and action-type, is first sighted in by firing ammunition at a target. Then the bore support member is positioned in the firearm bore so the collimator objective lens is in line with the sights. Next the sighting grid position is adjusted to align the collimator optic axis with the optic axis of the sights on the firearm. After having aligned the sighting grid, the collimator arrangement with bore support member is mounted on other firearms of the same type and sights on these firearms are aligned with the optic axis of the collimator arrangement. Sights on other firearms types can similarly be aligned. However, one firearm of each type must be preserved as a master or the entire process must be repeated to include sighting in with live ammunition. Accordingly, this known collimator device and method requires maintaining master firearms such that sights are not misaligned.